Inelastic electron tunneling spectroscopy of phenol and hydroquinone chemisorbed on alumina

Inelastic electron tunneling spectroscopy has been used to probe the irreversible chemisorption of C6H 50H and 1,4-C6H 4(0H)2 on a thin amorphous film of Al20 3• This spectroscopy yields a representation of the vibronic excitations of the chemical bonds in the adspecies, i.e., the tunneling spectra are analogous to ir spectra. The C6H 50H is found to adsorb predominately as C6H 50with a small amount of adsorption as C6H 50H. The 1,4-C~4(0H)2 is found to adsorb predominately as C6H4(0H)Oand perhaps to a smaller extent as C6H40f-. Extensive hydrogen bonding is observed among adsorbates and between adsorbates and the hydroxylated alumina surface.